The Impact of Extrusion Process Variables on the Physicochemical and Sensory Qualities of Maize (Zea mays), Bambara Groundnut (Vigna subterranea), and Sweet Potato (Ipomoea batatas) Based Extruded Products

Abstract

Snack foods are typically designed to be portable, quick, and satisfying. High-temperature extrusion for a short duration "minimizes losses in vitamins and amino acids". Since protein-energy malnutrition and micronutrient deficiencies are widely prevalent, the utilization of underutilized legumes (bambara groundnuts) for the supplementation of starch-based foods is essential. This work determined the effect of extrusion variables on the physicochemical and sensory properties of the snacks. The flour particle size, moisture level, screw speed, and die diameter (4mm) were kept constant throughout the process while the feed composition and barrel temperatures were varied. The expansion ratio and bulk density of the extrudate ranged from 0.51±0.44 to 0.807±0.012 and 0.727±0.111 to 0.803±0.033 gcm-3 respectively. As for proximate composition, the moisture content ranged from (5.167±0.116 to 4.00±0.1661 %), Protein (8.623±0.337 to 13.950±0.812%), Fat (1.833±0.011 to 4.300±0.112%), crude fiber (2.587±0.112 to 3.40±0.178%), Ash (0.833±0.012 to 1.817±0.091%) and carbohydrate (73.09±0.881 to 80.460±0.112%), respectively all at varying temperatures and feed compositions. The sensory attributes of the snack ranged from 3.823±0.119 to 6.730±0.073 for appearance, 3.73±0.091 to 6.583±0.073 for flavour, from 4.00±0.571 to 4.840±0.331 for texture, with a significant difference as influenced by the feed compositions and barrel temperatures but sample Fc3Bt3 had the highest percentage of overall acceptability 6.667±0.117 as influenced by extrusion variables.